Night vision devices, such as night vision goggles (NVG's) are well known for being able to enable a user of such a device to easily see in darkened environments. These devices are often used in military applications to enable soldiers to see without the use of extraneous visible lighting, such as flashlights, which may give away their position to the enemy. The NVG intensifies the available low-level ambient light, and provides an image having a generally greenish glow that enables the user to see his surroundings.
The NVG is often mounted on a soldier's helmet and is movable between an operational position in front of the soldier's eyes, and a stowed position, such as above the soldier's eyes. However, in the stowed position, the eyepieces are generally directed outward, away from the soldier, and it may be possible for an enemy to see the green glow from the eyepieces, thus giving away the soldier's position.
To counter this problem, magnets have been incorporated in the helmet is mount so that, when the NVG is in its use position, the magnetic field generated by the magnet activates a magnetically operable switchpot, turning the NVG “ON”. When the NVG is flipped to is stowed position, the magnet slides within its housing away from the magnetic switchpot, removing the magnetic field, and turning the NVG “OFF”. However, problems exist with this technology. When the soldier is not looking in a level direction, but is looking up or down, the magnet may inadvertently slide to the “OFF” position, rendering the NVG inoperable at an inopportune time. Additionally, if the soldier is rolling or tumbling, the magnet may again slide to the “OFF” position. Further, the magnet slides within its housing with an audible “click” that may disturb soldiers fearful of generating any sound whatsoever that may give away their position to the enemy.
It would be beneficial to provide a method of maintaining the NVG in the “ON” position when the NVG is in front of the soldier's eyes, regardless of the soldier's orientation, yet automatically switchpot to the “OFF” position when the NVG is moved away from the soldier's eyes.